RE: Heart pacemakers - Vulnerability to EM
Hi Dave and Net, Transmitting at 160m (1.8MHz) in an operating position with about 600V/m in my amateur radio stations (HB9CVQ/DK2VQ) would certainly make me search for a reduction method to lower the fields to less than 20 V/m. I tested this with 1 kW output and a calibrated field strength monitor (Narda Safety Test Systems) in CW-mode. Setup: Antenna G5RV , short dipole 2x15.4m, normally 9.85m 450 Ohm open wire feeder, at 160m extension with extra 17,5m 450 Ohm line, common mode choke (35dB) , 3.5m RG213, asymmetrical tuner, TL922, IC-761. All equipment is shielded and properly grounded (max. I CM < 10mA anywhere at 1kW-reference ground plane below equipment desk installed-open zoning concept). The antenna feed point is about 7m away with the feed line being perfectly in the symmetry plane of the ant. The end of the feed line is about 2m away from the operating position. With just the 9.85m feeder line and 15 uH inductance , about 30 cm diameter, open-no shield, real low loss inductors at the end, to tune the line on each side, I got 1.5 KV/m in the operating position-about 1,3m away only with 100W output on 1.85MHz! That made me worry to change very quickly. Efficiency of this new antenna system (additional extended feeder by 17.5m- coiled up on 40cm diameter) is naturally reduced over a full half wave dipole, but reasonable for the restricted space. In publicly accessible areas near the antenna (feed point 12m up and ends down to 9m height above ground) the E-field drops to about 1V/m at full legal 1kW level. By the way measuring very near a metallic surface can sometimes produce strange readings with E-field probes, better check the surface currents with a suitable probe. I hope these comments are useful Diethard Hansen Best regards Dr. Diethard Hansen EES President, Principal Consultant, Trainer US Senior NARTE certif. EMC Eng. 001937NE EMC+Automotive+Telecom QM+techn. EA-Auditor Euro EMC SERVICE (EES) Dr.-Ing. D. Hansen POB 64, Bahnhofstr.39, CH-8965 Berikon 2, Switzerland, Swiss VAT (Mwst.)No.:323214 tel./fax: +41 566 33 73 81 German mobile phone: +49(0)1736015909 www.euro-emc-service.de <http://www.euro-emc-service.de> euro.emc.serv...@swissonline.ch <mailto:euro.emc.serv...@swissonline.ch> ( mailto:diethard.han...@ieee.org <mailto:diethard.han...@ieee.org> ) Consulting+Seminars+R&D-Projects Marketing+CE-Testing+ww.Audits From: owner-emc-p...@listserv.ieee.org [mailto:owner-emc-p...@listserv.ieee.org]On Behalf Of drcuthb...@micron.com Sent: Freitag, 19. November 2004 15:47 To: israe...@oms-it.co.il; emc-p...@ieee.org Subject: RE: Heart pacemakers - Vulnerability to EM I don't know what the standards call for but it is quite possible for a person to be subjected to an E-field exceeding 500 V/m very near to an amateur radio station. This is the field at my operating position when I am transmitting at 1.8 MHz. A cell phone held close to the body will cause a field, at the body, of over 30 V/m. Dave Cuthbert From: owner-emc-p...@listserv.ieee.org [mailto:owner-emc-p...@listserv.ieee.org] On Behalf Of Israel Sent: Thursday, November 18, 2004 4:55 PM To: emc-p...@ieee.org Subject: Heart pacemakers - Vulnerability to EM Hi all Heart pacemakers may be vulnerable to Electro Magnetic energy. Has anyone idea about safe immunity levels ? about relevant standards regarding this matter ? Thanks ! This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Scott Douglas emcp...@ptcnh.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Scott Douglas emcp...@ptcnh.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message
Re: Heart pacemakers - Vulnerability to EM
It may be worth noting that in the medium wave broadcast band the FCC limit is over 600 volts per meter. We don't incur inherently harmful induced body currents with less at these frequencies -- unless we're hanging onto an antenna. But considering the low potentials to be measured, and the energy delivered by a pacer or defibrillator, it seems difficult to adequately filter device leads from all fields they might see, so we have the fall-back constant pacing mode mentioned before. In my opinion, the immunity levels required by the Medical Directive are not unreasonable, even if they may be encountered rarely; one report extant on the Web is of a patient who subjected to search by an airport security wand, which caused his implanted, computerized drug delivery system to deliver a non-survivable level of drugs. Inductive coupling directly to devices and leads is quite probably a harsher environment than being near a broadcast antenna. But all too common! Cortland Richmond This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Scott Douglas emcp...@ptcnh.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Heart pacemakers - Vulnerability to EM
But there is a very big difference between the two fields Mr. Cuthbert cites, aside from frequency. The cell phone field likely has a field impedance close to that of free space, because the antenna is a good match to the transmitter. Unless your tower is around 100' and operating as a base fed quarter-wave stub, you are likely using a tuning device to step up the output potential of your transmitter to more effectively drive a shorter stub radiator. The net effect is that in the very near field the ratio of electric to magnetic field is very much higher than 377 Ohms. The susceptibility effect of such a quasi-static electric field is very different than for a plane wave, especially if the EUT is surrounded by a shielding material, such as the human body, or any metallic shielding material one might choose to employ. A conclusion I would draw from this is that if it were deemed necessary to simulate the near field of an amateur radio site or an AM broadcast station, I would use an open-circuited parallel plate, as opposed to one loaded by 50 Ohms or other matching impedance. From: drcuthb...@micron.com List-Post: emc-pstc@listserv.ieee.org Date: Fri, 19 Nov 2004 07:46:59 -0700 To: , Subject: RE: Heart pacemakers - Vulnerability to EM I don't know what the standards call for but it is quite possible for a person to be subjected to an E-field exceeding 500 V/m very near to an amateur radio station. This is the field at my operating position when I am transmitting at 1.8 MHz. A cell phone held close to the body will cause a field, at the body, of over 30 V/m. Dave Cuthbert From: owner-emc-p...@listserv.ieee.org mailto:owner-emc-p...@listserv.ieee.org] On Behalf Of Israel Sent: Thursday, November 18, 2004 4:55 PM To: emc-p...@ieee.org Subject: Heart pacemakers - Vulnerability to EM Hi all Heart pacemakers may be vulnerable to Electro Magnetic energy. Has anyone idea about safe immunity levels ? about relevant standards regarding this matter ? Thanks ! This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Scott Douglas emcp...@ptcnh.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Scott Douglas emcp...@ptcnh.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Scott Douglas emcp...@ptcnh.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Heart pacemakers - Vulnerability to EM
I have just a bit of personal experience in testing implantable pacemakers and
volumetric infusion pumps. I had been doing RF immunity studies for a
manufacturer, circa 1990, using an FDA standard (MDS-401-xxx?) for medical
electronic devices.
I exposed devices to fields as strong as I could create (10 kHz through 18
GHz, always at least 200 V/M, sometimes as high as 600 V/M), using both 1 kHz,
50% duty cycle and a 200 Hz, 10% duty cycle, gated at a 1 Hz rate. The devices
were tested first in open air, and then immersed in a rectangular tank of
saline solution (a crude attempt to simulate body tissue). I also exposed them
to 20 Oersted DC & 60 Hz magnetic fields (the infusion pumps had a magnetic
communications link for programming and monitoring).
The nice part is that, after some design changes, I was unable to elicit any
improper responses from the devices. Since these devices were so nicely
immune, I imagine that a person would feel the effects of tissue heating well
before the electronics are jeopardized.
I hope they still make them as good now.
Ed
Ed Price
ed.pr...@cubic.com WB6WSN
NARTE Certified EMC Engineer & Technician
Electromagnetic Compatibility Lab
Cubic Defense Applications
San Diego, CA USA
858-505-2780 (Voice)
858-505-1583 (Fax)
Military & Avionics EMC Is Our Specialty
From: Barker, Neil [ mailto:neil.bar...@e2v.com]
Sent: Friday, November 19, 2004 8:20 AM
To: 'drcuthb...@micron.com'; israe...@oms-it.co.il; emc-p...@ieee.org
Subject: RE: Heart pacemakers - Vulnerability to EM
I am no expert in this subject, and some of what I am about to say is
hearsay, but here it is for what it's worth.
Safety levels are generally based not on field strength, but on power
density. However, these levels are set for the power absorption of the body
(in W/kg) based on the heating effect. For comparison purposes consider the
acceptance levels applied to SAR testing. On this basis, I suspect that Dave's
amateur rig probably doesn't meet SAR acceptance levels, and should probably
have an exclusion zone around the antenna!
The original message was concerned with the effect on a pacemaker
rather than directly on the body itself. Clearly, if you disrupt a pacemaker
then it is the pacemaker that has an effect on the body.
I believe that the susceptibility depends greatly on whether they are
external pacemakers or implanted pacemakers. The implanted devices are much
less susceptible as they are completely surrounded by soft body tissue, which
is largely water in any case. External devices are much more susceptible, due
largely to the relatively long electrode wire. being long, this is generally
susceptible at fairly low frequencies, and I have heard that they can be
affected by the magnetic loops used in store doorways for security
(merchandise protection) purposes. I have no knowledge of their susceptibility
to E fields.
Best regards,
Neil R. Barker C.Eng. MIEE FSEE MIEEE
Manager
Compliance Engineering
e2v technologies (uk) ltd
106 Waterhouse Lane
Chelmsford
Essex
CM1 2QU
UK
Tel: +44 (0)1245 453616
Fax: +44 (0)1245 453410
e-mail: neil.bar...@e2v.com
Web: http://www.e2v.com < http://www.e2v.com/>
-Original Message-
From: drcuthb...@micron.com [ mailto:drcuthb...@micron.com]
Sent: 19 November 2004 14:47
To: israe...@oms-it.co.il; emc-p...@ieee.org
Subject: RE: Heart pacemakers - Vulnerability to EM
I don't know what the standards call for but it is quite
possible for a person to be subjected to an E-field exceeding 500 V/m very
near to an amateur radio station. This is the field at my operating position
when I am transmitting at 1.8 MHz. A cell phone held close to the body will
cause a field, at the body, of over 30 V/m.
Dave Cuthbert
-Original Message-
From: owner-emc-p...@listserv.ieee.org [
mailto:owner-emc-p...@listserv.ieee.org] On Behalf Of Israel
Sent: Thursday, November 18, 2004 4:55 PM
To: emc-p...@ieee.org
Subject: Heart pacemakers - Vulnerability to EM
Hi all
Heart pacemakers may be vulnerable to Electro Magnetic energy.
Has anyone idea about safe immunity levels ? about relevant standards
regarding this matter ?
Thanks !
This message
is from the IEEE Product Saf
RE: Heart pacemakers - Vulnerability to EM
The standards EN 50061 /EN 45502-2-1 are dealing with the immunity of pace makers. Immunity is tested in a torso simulator and a specific antenna to transmit close to water at the right frequency. The problem is not the pacemaker itself, it is the fact that the sensors provide a good antenna. Beside this modern pace makers additionally have a mode of operation they go into if they got interference with a certain level above the normal interference they have. They don’t sense anymore and got to a fixed rhythm. Even with that relatively high level of immunity there are devices people with pace makers have to stay away like high power transformers and all devices creating a high magnetic field (MRT). Electric shavers, hairdryers and tolls like electric drills also have a potential to disturb the function if used close to the pace maker. Lothar Schmidt Technical Manager EMC, SAR, Antenna testing and BQB CETECOM Inc. 411 Dixon Landing Road Milpitas, CA 95035 Phone +1 408 586 6214 Fax +1 408 586 6299 This e-mail may contain proprietary, privileged and confidential information for the sole use of the named intended recipient. Any review or distribution of this e-mail by any party other than the intended recipient or that person's agent is strictly prohibited. If you are not the intended recipient, please delete all copies and immediately Contact the sender. You must not, directly or indirectly, use, disclose, distribute, print, or copy any part of this message if you are not the intended recipient. Thank you. _ From: owner-emc-p...@listserv.ieee.org mailto:owner-emc-p...@listserv.ieee.org] On Behalf Of Barker, Neil Sent: Friday, November 19, 2004 8:20 AM To: 'drcuthb...@micron.com'; israe...@oms-it.co.il; emc-p...@ieee.org Subject: RE: Heart pacemakers - Vulnerability to EM I am no expert in this subject, and some of what I am about to say is hearsay, but here it is for what it's worth. Safety levels are generally based not on field strength, but on power density. However, these levels are set for the power absorption of the body (in W/kg) based on the heating effect. For comparison purposes consider the acceptance levels applied to SAR testing. On this basis, I suspect that Dave's amateur rig probably doesn't meet SAR acceptance levels, and should probably have an exclusion zone around the antenna! The original message was concerned with the effect on a pacemaker rather than directly on the body itself. Clearly, if you disrupt a pacemaker then it is the pacemaker that has an effect on the body. I believe that the susceptibility depends greatly on whether they are external pacemakers or implanted pacemakers. The implanted devices are much less susceptible as they are completely surrounded by soft body tissue, which is largely water in any case. External devices are much more susceptible, due largely to the relatively long electrode wire. being long, this is generally susceptible at fairly low frequencies, and I have heard that they can be affected by the magnetic loops used in store doorways for security (merchandise protection) purposes. I have no knowledge of their susceptibility to E fields. Best regards, Neil R. Barker C.Eng. MIEE FSEE MIEEE Manager Compliance Engineering e2v technologies (uk) ltd 106 Waterhouse Lane Chelmsford Essex CM1 2QU UK Tel: +44 (0)1245 453616 Fax: +44 (0)1245 453410 e-mail: neil.bar...@e2v.com Web: http://www.e2v.com <http://www.e2v.com/> From: drcuthb...@micron.com [mailto:drcuthb...@micron.com] Sent: 19 November 2004 14:47 To: israe...@oms-it.co.il; emc-p...@ieee.org Subject: RE: Heart pacemakers - Vulnerability to EM I don't know what the standards call for but it is quite possible for a person to be subjected to an E-field exceeding 500 V/m very near to an amateur radio station. This is the field at my operating position when I am transmitting at 1.8 MHz. A cell phone held close to the body will cause a field, at the body, of over 30 V/m. Dave Cuthbert From: owner-emc-p...@listserv.ieee.org mailto:owner-emc-p...@listserv.ieee.org] On Behalf Of Israel Sent: Thursday, November 18, 2004 4:55 PM To: emc-p...@ieee.org Subject: Heart pacemakers - Vulnerability to EM Hi all Heart pacemakers may be vulnerable to Electro Magnetic energy. Has anyone idea about safe immunity levels ? about relevant standards regarding this matter ? Thanks ! This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Scott Douglas
RE: Heart pacemakers - Vulnerability to EM
I am no expert in this subject, and some of what I am about to say is hearsay, but here it is for what it's worth. Safety levels are generally based not on field strength, but on power density. However, these levels are set for the power absorption of the body (in W/kg) based on the heating effect. For comparison purposes consider the acceptance levels applied to SAR testing. On this basis, I suspect that Dave's amateur rig probably doesn't meet SAR acceptance levels, and should probably have an exclusion zone around the antenna! The original message was concerned with the effect on a pacemaker rather than directly on the body itself. Clearly, if you disrupt a pacemaker then it is the pacemaker that has an effect on the body. I believe that the susceptibility depends greatly on whether they are external pacemakers or implanted pacemakers. The implanted devices are much less susceptible as they are completely surrounded by soft body tissue, which is largely water in any case. External devices are much more susceptible, due largely to the relatively long electrode wire. being long, this is generally susceptible at fairly low frequencies, and I have heard that they can be affected by the magnetic loops used in store doorways for security (merchandise protection) purposes. I have no knowledge of their susceptibility to E fields. Best regards, Neil R. Barker C.Eng. MIEE FSEE MIEEE Manager Compliance Engineering e2v technologies (uk) ltd 106 Waterhouse Lane Chelmsford Essex CM1 2QU UK Tel: +44 (0)1245 453616 Fax: +44 (0)1245 453410 e-mail: neil.bar...@e2v.com Web: http://www.e2v.com <http://www.e2v.com/> From: drcuthb...@micron.com [mailto:drcuthb...@micron.com] Sent: 19 November 2004 14:47 To: israe...@oms-it.co.il; emc-p...@ieee.org Subject: RE: Heart pacemakers - Vulnerability to EM I don't know what the standards call for but it is quite possible for a person to be subjected to an E-field exceeding 500 V/m very near to an amateur radio station. This is the field at my operating position when I am transmitting at 1.8 MHz. A cell phone held close to the body will cause a field, at the body, of over 30 V/m. Dave Cuthbert From: owner-emc-p...@listserv.ieee.org mailto:owner-emc-p...@listserv.ieee.org] On Behalf Of Israel Sent: Thursday, November 18, 2004 4:55 PM To: emc-p...@ieee.org Subject: Heart pacemakers - Vulnerability to EM Hi all Heart pacemakers may be vulnerable to Electro Magnetic energy. Has anyone idea about safe immunity levels ? about relevant standards regarding this matter ? Thanks ! This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Scott Douglas emcp...@ptcnh.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Heart pacemakers - Vulnerability to EM
I don't know what the standards call for but it is quite possible for a person to be subjected to an E-field exceeding 500 V/m very near to an amateur radio station. This is the field at my operating position when I am transmitting at 1.8 MHz. A cell phone held close to the body will cause a field, at the body, of over 30 V/m. Dave Cuthbert From: owner-emc-p...@listserv.ieee.org mailto:owner-emc-p...@listserv.ieee.org] On Behalf Of Israel Sent: Thursday, November 18, 2004 4:55 PM To: emc-p...@ieee.org Subject: Heart pacemakers - Vulnerability to EM Hi all Heart pacemakers may be vulnerable to Electro Magnetic energy. Has anyone idea about safe immunity levels ? about relevant standards regarding this matter ? Thanks ! This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Scott Douglas emcp...@ptcnh.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Scott Douglas emcp...@ptcnh.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
